Potential Snow 11/27 - 11/28

[MJO812]

0z Nam

http://mag.ncep.noaa.gov/NCOMAGWEB/appcontroller?prevPage=Model&MainPage=indexℑ=&page=Param&cycle=11%2F26%2F2012+00UTC&rname=SFC-LAYER+PARMS&pname=sim_radar&pdesc=&model=NAM&area=NAMER&cat=MODEL+GUIDANCE&fcast=042&areaDesc=North+America+-+US+Canada+and+northern+Mexico&prevArea=NAMER&currKey=model&returnToModel=&imageSize=M

[Zelocita Weather]

0z nam looks like a solid 1-3" deal for most of area with around .25" for most...decent amount juicier than recent runs

[famartin]

0z Nam

http://mag.ncep.noaa...el=&imageSize=M

Warmer too, though.

[famartin]

0z nam looks like a solid 1-3" deal for most of area with around .25" for most...decent amount juicier than recent runs

Well inland, maybe. In NYC that's plain rain.

[rgwp96]

Well inland, maybe. In NYC that's plain rain.

and about 800-100o ft in elevation

[MJO812]

Well inland, maybe. In NYC that's plain rain.

Yes but you have to say this run is much better than the previous runs. This doesn't look like all rain for the coast.

[famartin]

Yes but you have to say this run is much better than the previous runs. This doesn't look like all rain for the coast.

Actually yeah, it does.

Edit: OK, maybe a little wet snow right at the start.

[MJO812]

Actually yeah, it does.

We will see what happens. If the models get stronger with this storm, I doubt it will be all rain for the coast. I'm not talking about accumulating snow here. I am just talking about snow falling. I don't think we will see a lot of snow accumulations. I could see Dusting to an 1inch.

[famartin]

We will see what happens. If the models get stronger with this storm, I doubt it will be all rain for the coast.

That's not what you said.

[Mitchel Volk]

Seems like the 850-1000mb thickness may be a bit too high. However if NYC gets into the heavier band and the storm is a little more intense it may cool off enough to snow.

[Mr Torchey]

We will see what happens. If the models get stronger with this storm, I doubt it will be all rain for the coast.

That is waa precip, nothing to do with a strengthening storm.

[famartin]

Seems like the 850-1000mb thickness may be a bit too high. However if NYC gets into the heavier band and the storm is a little more intense it may cool off enough to snow.

Yeah, looking further south it actually tries to do that around Philly.

[earthlight]

Thermal profiles are too warm anywhere within 25 miles from the coast for prolonged snow or accumulation. There is no good lift or heavy precip to cool the column.

[Snow_Miser]

Precip types at hr 39.

Nice run for inland locations.

hr 42:

[famartin]

Clown maps for the NAM... its a west-of-Philly jackpot.

[Nikolai]

Hopefully NYC can steal their snow again.

These kinds of events seem to come in significantly before forecast, most every time. I would watch for the NAM to get colder as we get closer. Accumulations unlikely unless there's a major surprise but we could definitely see flakes in the air.

[Storm At Sea]

I say it over and over again like a broken record....Use the SREF! I can't tell you how they are very accurate more times than not. HPC uses the SREF to produce their heavy snowfall graphics (an normally use them verbatim).

For this event, the SREF's are saying what every reasonable meteorologist is stating on this board: as of now, this is an inland snow event...accumulating snow for inland PA and NW NJ. Sure, coast and C NJ may get some mixing in at times, but not a big event especially given the timing of the event (accumulating snow in late Nov. at 3PM is difficult given even the best of circumstances).

I think people should be more attuned with getting the Pacific in order so that we can develop some cold. I don't see anything in the next 7 days. However, given the AO and NAO staying negative for the next week, I suspect that the GFS/Euro are having a tough time. I'm not expecting 50's on Dec. 5 is all I can say (though I might be wrong).

Hopefully NYC can steal their snow again.

These kinds of events seem to come in significantly before forecast, most every time. I would watch for the NAM to get colder as we get closer. Accumulations unlikely unless there's a major surprise but we could definitely see flakes in the air.

[Guest Pamela]

Say what you will, but I think this will likely be a mostly snow event for NYC and much of Long Island. The NAM is, IMO, too warm with the 2m temps. With temps @ 850 mb around -5 C, but more importantly, virtually no wind, it will be very difficult to bring warm air onshore....whatever wind there is, should eventually shift light into the northeast. This is no storm where there is some type of protracted flow off the water...just a weak wave moving through. Saw lots of these in the 1980's where the surface never gets higher than about 33 F. The models also came in wetter at 0z, (NMM was *very* wet), so for now, I'll go for one to four inches of snow on Tuesday for NYC and Long Island.

[famartin]

0Z EC backed way off... only 0.11" in Central Park. Also got warmer probably due to less precip.

[famartin]

NAM is a bit wetter, but still mostly rain for NYC. Further southwest its snowier, for sure.

[famartin]

GFS is also a tad wetter at 06z, though not to the degree of the nam.

Hmm, its actually a smidge drier down at TTN... 0.23" vs 0.26". I don't think NYC is really any wetter, either, though I am comparing one earlier source with a different source for the most recent run.

[billgwx]

NAM is a bit wetter, but still mostly rain for NYC. Further southwest its snowier, for sure.

Am nervous about those boundary layer temps. Latent heat absorption by melting snow might wipe out any surface-based warm layer, which could make this event mostly snow. Models mishandled this on 11/7, and I suspect they may be mishandling it with this upcoming event.

[famartin]

Am nervous about those boundary layer temps. Latent heat absorption by melting snow might wipe out any surface-based warm layer, which could make this event mostly snow. Models mishandled this on 11/7, and I suspect they may be mishandling it with this upcoming event.

Well remember, the 11/7 event dropped an inch of liquid on NYC. That was the real surprise IMHO. If this event did that, then yeah I'd expect 5-10" of snow. But I don't think this event will even come remotely close.

[PB GFI]

Am nervous about those boundary layer temps. Latent heat absorption by melting snow might wipe out any surface-based warm layer, which could make this event mostly snow. Models mishandled this on 11/7, and I suspect they may be mishandling it with this upcoming event.

Yes, but the 7 ths system was working w .50 to .75 qpf to work with, so rates did the trick . This system is working with .10 to .20 and I guess thats been my issue for the last few days with this system

[famartin]

One other thing to remember... yes 11/7 was a bust on the snowy side for NYC... but it was a bust on the non-snowy side for PHL... where 0.39" of liquid resulted in only a TRACE of snow. Its all about the rates, like PB GFI just said. If you get a heavy precip band, then yeah it can defeat the warmer BL. I just looked at a few NAM soundings I saved for PHL from before 11/7 and they showed the warm BL which actually verified perfectly there. Because the rates weren't able to defeat it.

[famartin]

Here's one of the soundings I was talking about. This verified at the surface like so:

METAR KPHL 072354Z 34014G20KT 8SM -RA SCT012 OVC020 02/01 A2987 RMK AO2 SLP115 P0004 60027 T00220006 10033 20017 50002 $

For those who can't read METAR, that's 36F with light rain, 0.04" of precip in the previous hour. It verified because the precip rate was too low to defeat the warm BL.

[famartin]

And just to drive the point down a little bit more, here's KNYC's METAR from the same time:

METAR KNYC 072351Z AUTO 36010G26KT 320V050 1/4SM +SN FZFG VV006 M01/M01 A2985 RMK AO2 PK WND 34026/2342 SLP099 P0012 60067 T10061006 10028 21006 58003 $

Heavy snow, 31F with 0.12" liquid equivalent in the previous hour. That's three times the precip rate Philly had. And, I might mention, almost as much is expected during the entire event on Tuesday, at least per some models.

[Snow_Miser]

Hmm, its actually a smidge drier down at TTN... 0.23" vs 0.26". I don't think NYC is really any wetter, either, though I am comparing one earlier source with a different source for the most recent run.

Whoops, I thought the 06z was the 00z. Disregard my post.

[Snow_Miser]

6z GEFS looks about the same. A little over .25" in KTTN.

[Sundog]

And just to drive the point down a little bit more, here's KNYC's METAR from the same time:

METAR KNYC 072351Z AUTO 36010G26KT 320V050 1/4SM +SN FZFG VV006 M01/M01 A2985 RMK AO2 PK WND 34026/2342 SLP099 P0012 60067 T10061006 10028 21006 58003 $

Heavy snow, 31F with 0.12" liquid equivalent in the previous hour. That's three times the precip rate Philly had. And, I might mention, almost as much is expected during the entire event on Tuesday, at least per some models.

Your point is clear and undeniable. This is a nonevent for the vast majority of the subforum.